The use of a thinner gasket instead of the Cork should fix the problem you are talking about. The center of the plate will not move away from that area. FWIW
Not many around here Rev their SBM to 8 or 9K..... Awesome that some can!
The thick cork is part of the 3 piece kit for the 90 adpter. The plate takes one piece or two piece same thicness. Inner and outer. The one piece is both inner and outer connected by three fingers.